Articles | Volume 21, issue 6
https://doi.org/10.5194/acp-21-5195-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-21-5195-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
01 Apr 2021
Research article |
| 01 Apr 2021
| 01 Apr 2021
How frequent is natural cloud seeding from ice cloud layers ( < −35 °C) over Switzerland?
Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
Verena Bessenbacher
Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
Zane Dedekind
Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
Ulrike Lohmann
Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
David Neubauer
Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
Related authors
Janneke O. E. Remmers, Rozemarijn ter Horst, Ehsan Nabavi, Ulrike Proske, Adriaan J. Teuling, Jeroen Vos, and Lieke A. Melsen
Hydrol. Earth Syst. Sci., 29, 5371–5382, https://doi.org/10.5194/hess-29-5371-2025, https://doi.org/10.5194/hess-29-5371-2025, 2025
Short summary
Short summary
Hydrological models are generally seen as neutral, despite acknowledged uncertainties. This notion has several, possibly harmful, consequences. In critical social sciences, non-neutrality in methods and results is an established topic of debate. We propose that in order to deal with it in hydrological modelling, the hydrological modelling network can learn from, and with, critical social sciences. The main lesson, from our perspective, is that responsible modelling is a shared responsibility.
Luis A. Ladino, Karin Ardon-Dryer, Diana L. Pereira, Ulrike Proske, Zyanya Ramirez-Diaz, Antonia Velicu, and Zamin A. Kanji
EGUsphere, https://doi.org/10.5194/egusphere-2025-4499, https://doi.org/10.5194/egusphere-2025-4499, 2025
This preprint is open for discussion and under review for Geoscience Communication (GC).
Short summary
Short summary
A survey and literature metadata analysis from the cloud physics community are used to investigate the state of diversity, equity and inclusion in the cloud physics research community. We show the evolution of gender contributions to cloud physics and the inclusion of scientists from the Global South. The publication analysis reveals the rate of men and women dropping out of the field is not different, however, gender balance was better achieved when women led publications compared to men.
Ken S. Carslaw, Leighton A. Regayre, Ulrike Proske, Andrew Gettelman, David M. H. Sexton, Yun Qian, Lauren Marshall, Oliver Wild, Marcus van Lier-Walqui, Annika Oertel, Saloua Peatier, Ben Yang, Jill S. Johnson, Sihan Li, Daniel T. McCoy, Benjamin M. Sanderson, Christina J. Williamson, Gregory S. Elsaesser, Kuniko Yamazaki, and Ben B. B. Booth
EGUsphere, https://doi.org/10.5194/egusphere-2025-4341, https://doi.org/10.5194/egusphere-2025-4341, 2025
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
Short summary
Short summary
A major challenge in climate science is reducing projection uncertainty despite advances in models and observational constraints. Perturbed parameter ensembles (PPEs) offer a powerful tool to explore and reduce uncertainty by revealing model weaknesses and guiding development. PPEs are now widely applied across climate systems and scales. We argue they should be prioritized alongside complexity and resolution in model resource planning.
Hans Segura, Xabier Pedruzo-Bagazgoitia, Philipp Weiss, Sebastian K. Müller, Thomas Rackow, Junhong Lee, Edgar Dolores-Tesillos, Imme Benedict, Matthias Aengenheyster, Razvan Aguridan, Gabriele Arduini, Alexander J. Baker, Jiawei Bao, Swantje Bastin, Eulàlia Baulenas, Tobias Becker, Sebastian Beyer, Hendryk Bockelmann, Nils Brüggemann, Lukas Brunner, Suvarchal K. Cheedela, Sushant Das, Jasper Denissen, Ian Dragaud, Piotr Dziekan, Madeleine Ekblom, Jan Frederik Engels, Monika Esch, Richard Forbes, Claudia Frauen, Lilli Freischem, Diego García-Maroto, Philipp Geier, Paul Gierz, Álvaro González-Cervera, Katherine Grayson, Matthew Griffith, Oliver Gutjahr, Helmuth Haak, Ioan Hadade, Kerstin Haslehner, Shabeh ul Hasson, Jan Hegewald, Lukas Kluft, Aleksei Koldunov, Nikolay Koldunov, Tobias Kölling, Shunya Koseki, Sergey Kosukhin, Josh Kousal, Peter Kuma, Arjun U. Kumar, Rumeng Li, Nicolas Maury, Maximilian Meindl, Sebastian Milinski, Kristian Mogensen, Bimochan Niraula, Jakub Nowak, Divya Sri Praturi, Ulrike Proske, Dian Putrasahan, René Redler, David Santuy, Domokos Sármány, Reiner Schnur, Patrick Scholz, Dmitry Sidorenko, Dorian Spät, Birgit Sützl, Daisuke Takasuka, Adrian Tompkins, Alejandro Uribe, Mirco Valentini, Menno Veerman, Aiko Voigt, Sarah Warnau, Fabian Wachsmann, Marta Wacławczyk, Nils Wedi, Karl-Hermann Wieners, Jonathan Wille, Marius Winkler, Yuting Wu, Florian Ziemen, Janos Zimmermann, Frida A.-M. Bender, Dragana Bojovic, Sandrine Bony, Simona Bordoni, Patrice Brehmer, Marcus Dengler, Emanuel Dutra, Saliou Faye, Erich Fischer, Chiel van Heerwaarden, Cathy Hohenegger, Heikki Järvinen, Markus Jochum, Thomas Jung, Johann H. Jungclaus, Noel S. Keenlyside, Daniel Klocke, Heike Konow, Martina Klose, Szymon Malinowski, Olivia Martius, Thorsten Mauritsen, Juan Pedro Mellado, Theresa Mieslinger, Elsa Mohino, Hanna Pawłowska, Karsten Peters-von Gehlen, Abdoulaye Sarré, Pajam Sobhani, Philip Stier, Lauri Tuppi, Pier Luigi Vidale, Irina Sandu, and Bjorn Stevens
EGUsphere, https://doi.org/10.5194/egusphere-2025-509, https://doi.org/10.5194/egusphere-2025-509, 2025
Short summary
Short summary
The nextGEMS project developed two Earth system models that resolve processes of the order of 10 km, giving more fidelity to the representation of local phenomena, globally. In its fourth cycle, nextGEMS performed simulations with coupled ocean, land, and atmosphere over the 2020–2049 period under the SSP3-7.0 scenario. Here, we provide an overview of nextGEMS, insights into the model development, and the realism of multi-decadal, kilometer-scale simulations.
Ulrike Proske, Michael P. Adams, Grace C. E. Porter, Mark A. Holden, Jaana Bäck, and Benjamin J. Murray
Atmos. Chem. Phys., 25, 979–995, https://doi.org/10.5194/acp-25-979-2025, https://doi.org/10.5194/acp-25-979-2025, 2025
Short summary
Short summary
Ice-nucleating particles (INPs) aid the freezing of water droplets in clouds and thus modify cloud properties. In a campaign in a Finnish boreal forest, biological INPs were observed, despite many of their potential biological sources being snow-covered. We sampled tree-dwelling lichens that were not covered in snow and tested their ice nucleation ability in the laboratory. We found that the lichen harbours INPs, which may be important in similar snowy environments.
Ulrike Proske, Nils Brüggemann, Jan P. Gärtner, Oliver Gutjahr, Helmuth Haak, Dian Putrasahan, and Karl-Hermann Wieners
EGUsphere, https://doi.org/10.5194/egusphere-2024-3493, https://doi.org/10.5194/egusphere-2024-3493, 2024
Preprint archived
Short summary
Short summary
Climate models contain coding mistakes, which may look mundane, but can affect the results of interconnected and complex models in unforeseen ways. We describe a sea ice bug in the coupled atmosphere-ocean-sea ice model ICON, giving an example of visual and concise bug communication. This bug represents a novel species of resolution-dependent bugs. The case illustrates the value of open documentation of bugs in climate models and to encourage our community to adopt a similar approach.
Franziska Vogel, Michael P. Adams, Larissa Lacher, Polly B. Foster, Grace C. E. Porter, Barbara Bertozzi, Kristina Höhler, Julia Schneider, Tobias Schorr, Nsikanabasi S. Umo, Jens Nadolny, Zoé Brasseur, Paavo Heikkilä, Erik S. Thomson, Nicole Büttner, Martin I. Daily, Romy Fösig, Alexander D. Harrison, Jorma Keskinen, Ulrike Proske, Jonathan Duplissy, Markku Kulmala, Tuukka Petäjä, Ottmar Möhler, and Benjamin J. Murray
Atmos. Chem. Phys., 24, 11737–11757, https://doi.org/10.5194/acp-24-11737-2024, https://doi.org/10.5194/acp-24-11737-2024, 2024
Short summary
Short summary
Primary ice formation in clouds strongly influences their properties; hence, it is important to understand the sources of ice-nucleating particles (INPs) and their variability. We present 2 months of INP measurements in a Finnish boreal forest using a new semi-autonomous INP counting device based on gas expansion. These results show strong variability in INP concentrations, and we present a case that the INPs we observe are, at least some of the time, of biological origin.
Ulrike Proske, Sylvaine Ferrachat, and Ulrike Lohmann
Atmos. Chem. Phys., 24, 5907–5933, https://doi.org/10.5194/acp-24-5907-2024, https://doi.org/10.5194/acp-24-5907-2024, 2024
Short summary
Short summary
Climate models include treatment of aerosol particles because these influence clouds and radiation. Over time their representation has grown increasingly detailed. This complexity may hinder our understanding of model behaviour. Thus here we simplify the aerosol representation of our climate model by prescribing mean concentrations, which saves run time and helps to discover unexpected model behaviour. We conclude that simplifications provide a new perspective for model study and development.
Zane Dedekind, Ulrike Proske, Sylvaine Ferrachat, Ulrike Lohmann, and David Neubauer
Atmos. Chem. Phys., 24, 5389–5404, https://doi.org/10.5194/acp-24-5389-2024, https://doi.org/10.5194/acp-24-5389-2024, 2024
Short summary
Short summary
Ice particles precipitating into lower clouds from an upper cloud, the seeder–feeder process, can enhance precipitation. A numerical modeling study conducted in the Swiss Alps found that 48 % of observed clouds were overlapping, with the seeder–feeder process occurring in 10 % of these clouds. Inhibiting the seeder–feeder process reduced the surface precipitation and ice particle growth rates, which were further reduced when additional ice multiplication processes were included in the model.
Zoé Brasseur, Dimitri Castarède, Erik S. Thomson, Michael P. Adams, Saskia Drossaart van Dusseldorp, Paavo Heikkilä, Kimmo Korhonen, Janne Lampilahti, Mikhail Paramonov, Julia Schneider, Franziska Vogel, Yusheng Wu, Jonathan P. D. Abbatt, Nina S. Atanasova, Dennis H. Bamford, Barbara Bertozzi, Matthew Boyer, David Brus, Martin I. Daily, Romy Fösig, Ellen Gute, Alexander D. Harrison, Paula Hietala, Kristina Höhler, Zamin A. Kanji, Jorma Keskinen, Larissa Lacher, Markus Lampimäki, Janne Levula, Antti Manninen, Jens Nadolny, Maija Peltola, Grace C. E. Porter, Pyry Poutanen, Ulrike Proske, Tobias Schorr, Nsikanabasi Silas Umo, János Stenszky, Annele Virtanen, Dmitri Moisseev, Markku Kulmala, Benjamin J. Murray, Tuukka Petäjä, Ottmar Möhler, and Jonathan Duplissy
Atmos. Chem. Phys., 22, 5117–5145, https://doi.org/10.5194/acp-22-5117-2022, https://doi.org/10.5194/acp-22-5117-2022, 2022
Short summary
Short summary
The present measurement report introduces the ice nucleation campaign organized in Hyytiälä, Finland, in 2018 (HyICE-2018). We provide an overview of the campaign settings, and we describe the measurement infrastructure and operating procedures used. In addition, we use results from ice nucleation instrument inter-comparison to show that the suite of these instruments deployed during the campaign reports consistent results.
Ulrike Proske, Sylvaine Ferrachat, David Neubauer, Martin Staab, and Ulrike Lohmann
Atmos. Chem. Phys., 22, 4737–4762, https://doi.org/10.5194/acp-22-4737-2022, https://doi.org/10.5194/acp-22-4737-2022, 2022
Short summary
Short summary
Cloud microphysical processes shape cloud properties and are therefore important to represent in climate models. Their parameterization has grown more complex, making the model results more difficult to interpret. Using sensitivity analysis we test how the global aerosol–climate model ECHAM-HAM reacts to changes to these parameterizations. The model is sensitive to the parameterization of ice crystal autoconversion but not to, e.g., self-collection, suggesting that it may be simplified.
Janneke O. E. Remmers, Rozemarijn ter Horst, Ehsan Nabavi, Ulrike Proske, Adriaan J. Teuling, Jeroen Vos, and Lieke A. Melsen
Hydrol. Earth Syst. Sci., 29, 5371–5382, https://doi.org/10.5194/hess-29-5371-2025, https://doi.org/10.5194/hess-29-5371-2025, 2025
Short summary
Short summary
Hydrological models are generally seen as neutral, despite acknowledged uncertainties. This notion has several, possibly harmful, consequences. In critical social sciences, non-neutrality in methods and results is an established topic of debate. We propose that in order to deal with it in hydrological modelling, the hydrological modelling network can learn from, and with, critical social sciences. The main lesson, from our perspective, is that responsible modelling is a shared responsibility.
Christopher Fuchs, Fabiola Ramelli, Anna J. Miller, Nadja Omanovic, Robert Spirig, Huiying Zhang, Patric Seifert, Kevin Ohneiser, Ulrike Lohmann, and Jan Henneberger
Atmos. Chem. Phys., 25, 12177–12196, https://doi.org/10.5194/acp-25-12177-2025, https://doi.org/10.5194/acp-25-12177-2025, 2025
Short summary
Short summary
We quantify diffusional ice crystal growth in natural clouds using cloud seeding experiments. We report growth rates for 14 experiments between −5.1 °C and −8.3 °C and observe strong variations depending on the cloud characteristics. Comparing our growth rates to laboratory data, we found similar temperature-dependent trends, but the laboratory rates are higher. These data fill the gap in quantitative in situ observation of ice crystal growth, helping to validate models and laboratory experiments.
Luis A. Ladino, Karin Ardon-Dryer, Diana L. Pereira, Ulrike Proske, Zyanya Ramirez-Diaz, Antonia Velicu, and Zamin A. Kanji
EGUsphere, https://doi.org/10.5194/egusphere-2025-4499, https://doi.org/10.5194/egusphere-2025-4499, 2025
This preprint is open for discussion and under review for Geoscience Communication (GC).
Short summary
Short summary
A survey and literature metadata analysis from the cloud physics community are used to investigate the state of diversity, equity and inclusion in the cloud physics research community. We show the evolution of gender contributions to cloud physics and the inclusion of scientists from the Global South. The publication analysis reveals the rate of men and women dropping out of the field is not different, however, gender balance was better achieved when women led publications compared to men.
Huiying Zhang, Fabiola Ramelli, Christopher Fuchs, Nadja Omanovic, Anna J. Miller, Robert Spirig, Zhaolong Wu, Yunpei Chu, Xia Li, Ulrike Lohmann, and Jan Henneberger
EGUsphere, https://doi.org/10.5194/egusphere-2025-4397, https://doi.org/10.5194/egusphere-2025-4397, 2025
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
Short summary
Short summary
Ice crystals in clouds aggregate, shaping snow and rain, yet rates are hard to measure. Using cloud seeding, we sampled crystals downwind after known times. A deep-learning algorithm quantified aggregation by counting crystal components. Initial ice concentration was the main driver, confirmed by causal analysis, physics, and machine learning, though weaker than theory predicts. Temperature, size, and shape also mattered, while turbulence was negligible.
Ken S. Carslaw, Leighton A. Regayre, Ulrike Proske, Andrew Gettelman, David M. H. Sexton, Yun Qian, Lauren Marshall, Oliver Wild, Marcus van Lier-Walqui, Annika Oertel, Saloua Peatier, Ben Yang, Jill S. Johnson, Sihan Li, Daniel T. McCoy, Benjamin M. Sanderson, Christina J. Williamson, Gregory S. Elsaesser, Kuniko Yamazaki, and Ben B. B. Booth
EGUsphere, https://doi.org/10.5194/egusphere-2025-4341, https://doi.org/10.5194/egusphere-2025-4341, 2025
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
Short summary
Short summary
A major challenge in climate science is reducing projection uncertainty despite advances in models and observational constraints. Perturbed parameter ensembles (PPEs) offer a powerful tool to explore and reduce uncertainty by revealing model weaknesses and guiding development. PPEs are now widely applied across climate systems and scales. We argue they should be prioritized alongside complexity and resolution in model resource planning.
Kai Jeggle, David Neubauer, Hanin Binder, and Ulrike Lohmann
Atmos. Chem. Phys., 25, 7227–7243, https://doi.org/10.5194/acp-25-7227-2025, https://doi.org/10.5194/acp-25-7227-2025, 2025
Short summary
Short summary
This work uncovers the formation regimes of cirrus clouds and how dust particles influence their properties. By applying machine learning to a combination of satellite and reanalysis data, cirrus clouds are classified into different formation regimes. Depending on the regime, increasing dust aerosol concentrations can either decrease or increase the number of ice crystals. This challenges the idea of using cloud seeding to cool the planet, as it may unintentionally lead to warming instead.
Zane Dedekind, Alexei Korolev, and Jason Aaron Milbrandt
EGUsphere, https://doi.org/10.5194/egusphere-2025-3007, https://doi.org/10.5194/egusphere-2025-3007, 2025
Short summary
Short summary
We studied how airplane contrails form and persist under cold, moist conditions. Using computer simulations and real observations, we found that weather predicting models often underestimate moisture levels, limiting accurate trail prediction. Adjusting how ice grows in clouds allowed us to better simulate these contrails. Improving moisture representation in models can help predict the climate effects of these clouds.
Christopher Fuchs, Fabiola Ramelli, David Schweizer, Ulrike Lohmann, and Jan Henneberger
Atmos. Meas. Tech., 18, 2969–2986, https://doi.org/10.5194/amt-18-2969-2025, https://doi.org/10.5194/amt-18-2969-2025, 2025
Short summary
Short summary
We present a new instrument based on digital in-line holography (SmHOLIMO) for in situ cloud measurements. SmHOLIMO is designed to specifically measure small cloud droplets with diameters > 3.7 μm. This way we retrieve accurate cloud droplet size distributions, which are crucial to understand the evolution and governing microphysical processes of a cloud. Results of a field study are compared to co-located measurements of a second holographic imager, microwave radiometer, and cloud radar.
Guangyu Li, André Welti, Iris Thurnherr, Ulrike Lohmann, and Zamin A. Kanji
EGUsphere, https://doi.org/10.5194/egusphere-2025-2798, https://doi.org/10.5194/egusphere-2025-2798, 2025
Short summary
Short summary
This study presents ship-based measurements of summertime ice-nucleating particles (INPs) over the data-scarce Eurasian-Arctic Seas. We found that INPs are driven by both local and regional sources, with the highest levels observed near land and over ice-free waters. This study is highlighted for improving the understanding of INP abundance, sources, and their role in cloud processes in the rapidly warming Arctic.
Yusuf Bhatti, Duncan Watson-Parris, Leighton Regayre, Hailing Jia, David Neubauer, Ulas Im, Carl Svenhag, Nick Schutgens, Athanasios Tsikerdekis, Athanasios Nenes, Irfan Muhammed, Bastiaan van Diedenhoven, Ardit Arifi, Guangliang Fu, and Otto Hasekamp
EGUsphere, https://doi.org/10.5194/egusphere-2025-2848, https://doi.org/10.5194/egusphere-2025-2848, 2025
Short summary
Short summary
Aerosols (small airborne particles) impact Earth's climate, but their extent is unknown. By running climate model simulations and emulating millions of additional variants with different settings, we found that natural emissions like sea spray and sulfur are key sources of uncertainty in climate predictions. Our work shows that understanding these natural processes better can help improve climate models and make future climate projections more accurate.
Anna J. Miller, Christopher Fuchs, Fabiola Ramelli, Huiying Zhang, Nadja Omanovic, Robert Spirig, Claudia Marcolli, Zamin A. Kanji, Ulrike Lohmann, and Jan Henneberger
Atmos. Chem. Phys., 25, 5387–5407, https://doi.org/10.5194/acp-25-5387-2025, https://doi.org/10.5194/acp-25-5387-2025, 2025
Short summary
Short summary
We analyzed the ability of silver iodide particles (a commonly used cloud-seeding agent) to form ice crystals in naturally occurring liquid clouds at −5 to −8 °C and found that only ≈ 0.1 %−1 % of particles nucleate ice, with a negative dependence on temperature. By contextualizing our results with previous laboratory studies, we help to bridge the gap between laboratory and field experiments, which also helps to inform future cloud-seeding projects.
Sini Talvinen, Paul Kim, Emanuele Tovazzi, Eemeli Holopainen, Roxana Cremer, Thomas Kühn, Harri Kokkola, Zak Kipling, David Neubauer, João C. Teixeira, Alistair Sellar, Duncan Watson-Parris, Yang Yang, Jialei Zhu, Srinath Krishnan, Annele Virtanen, and Daniel G. Partridge
EGUsphere, https://doi.org/10.5194/egusphere-2025-721, https://doi.org/10.5194/egusphere-2025-721, 2025
Short summary
Short summary
Climate models struggle to predict how clouds and aerosols interact, affecting Earth’s energy balance. This study compares models to observations to see how they describe effects of clouds and rain on aerosols. While both models show similar overall trends, seasonal differences emerged. These, however, align with differences in key variables participating in cloud formation. The study provides tools to improve the representation of aerosol-cloud interactions in climate models.
George Jordan, Florent Malavelle, Jim Haywood, Ying Chen, Ben Johnson, Daniel Partridge, Amy Peace, Eliza Duncan, Duncan Watson-Parris, David Neubauer, Anton Laakso, Martine Michou, and Pierre Nabat
EGUsphere, https://doi.org/10.5194/egusphere-2025-835, https://doi.org/10.5194/egusphere-2025-835, 2025
Short summary
Short summary
The 2014–15 Holuhraun eruption created a vast aerosol plume that acted as a natural experiment to assess how well climate models capture changes in cloud properties due to increased aerosol. We find that the models accurately represent the observed shift to smaller, more numerous cloud droplets. However, the models diverge in their aerosol induced changes to large-scale cloud properties, particularly cloud liquid water content. Our study shows that Holuhraun had a cooling effect on the Earth.
Hans Segura, Xabier Pedruzo-Bagazgoitia, Philipp Weiss, Sebastian K. Müller, Thomas Rackow, Junhong Lee, Edgar Dolores-Tesillos, Imme Benedict, Matthias Aengenheyster, Razvan Aguridan, Gabriele Arduini, Alexander J. Baker, Jiawei Bao, Swantje Bastin, Eulàlia Baulenas, Tobias Becker, Sebastian Beyer, Hendryk Bockelmann, Nils Brüggemann, Lukas Brunner, Suvarchal K. Cheedela, Sushant Das, Jasper Denissen, Ian Dragaud, Piotr Dziekan, Madeleine Ekblom, Jan Frederik Engels, Monika Esch, Richard Forbes, Claudia Frauen, Lilli Freischem, Diego García-Maroto, Philipp Geier, Paul Gierz, Álvaro González-Cervera, Katherine Grayson, Matthew Griffith, Oliver Gutjahr, Helmuth Haak, Ioan Hadade, Kerstin Haslehner, Shabeh ul Hasson, Jan Hegewald, Lukas Kluft, Aleksei Koldunov, Nikolay Koldunov, Tobias Kölling, Shunya Koseki, Sergey Kosukhin, Josh Kousal, Peter Kuma, Arjun U. Kumar, Rumeng Li, Nicolas Maury, Maximilian Meindl, Sebastian Milinski, Kristian Mogensen, Bimochan Niraula, Jakub Nowak, Divya Sri Praturi, Ulrike Proske, Dian Putrasahan, René Redler, David Santuy, Domokos Sármány, Reiner Schnur, Patrick Scholz, Dmitry Sidorenko, Dorian Spät, Birgit Sützl, Daisuke Takasuka, Adrian Tompkins, Alejandro Uribe, Mirco Valentini, Menno Veerman, Aiko Voigt, Sarah Warnau, Fabian Wachsmann, Marta Wacławczyk, Nils Wedi, Karl-Hermann Wieners, Jonathan Wille, Marius Winkler, Yuting Wu, Florian Ziemen, Janos Zimmermann, Frida A.-M. Bender, Dragana Bojovic, Sandrine Bony, Simona Bordoni, Patrice Brehmer, Marcus Dengler, Emanuel Dutra, Saliou Faye, Erich Fischer, Chiel van Heerwaarden, Cathy Hohenegger, Heikki Järvinen, Markus Jochum, Thomas Jung, Johann H. Jungclaus, Noel S. Keenlyside, Daniel Klocke, Heike Konow, Martina Klose, Szymon Malinowski, Olivia Martius, Thorsten Mauritsen, Juan Pedro Mellado, Theresa Mieslinger, Elsa Mohino, Hanna Pawłowska, Karsten Peters-von Gehlen, Abdoulaye Sarré, Pajam Sobhani, Philip Stier, Lauri Tuppi, Pier Luigi Vidale, Irina Sandu, and Bjorn Stevens
EGUsphere, https://doi.org/10.5194/egusphere-2025-509, https://doi.org/10.5194/egusphere-2025-509, 2025
Short summary
Short summary
The nextGEMS project developed two Earth system models that resolve processes of the order of 10 km, giving more fidelity to the representation of local phenomena, globally. In its fourth cycle, nextGEMS performed simulations with coupled ocean, land, and atmosphere over the 2020–2049 period under the SSP3-7.0 scenario. Here, we provide an overview of nextGEMS, insights into the model development, and the realism of multi-decadal, kilometer-scale simulations.
Ulrike Proske, Michael P. Adams, Grace C. E. Porter, Mark A. Holden, Jaana Bäck, and Benjamin J. Murray
Atmos. Chem. Phys., 25, 979–995, https://doi.org/10.5194/acp-25-979-2025, https://doi.org/10.5194/acp-25-979-2025, 2025
Short summary
Short summary
Ice-nucleating particles (INPs) aid the freezing of water droplets in clouds and thus modify cloud properties. In a campaign in a Finnish boreal forest, biological INPs were observed, despite many of their potential biological sources being snow-covered. We sampled tree-dwelling lichens that were not covered in snow and tested their ice nucleation ability in the laboratory. We found that the lichen harbours INPs, which may be important in similar snowy environments.
Judith Kleinheins, Nadia Shardt, Ulrike Lohmann, and Claudia Marcolli
Atmos. Chem. Phys., 25, 881–903, https://doi.org/10.5194/acp-25-881-2025, https://doi.org/10.5194/acp-25-881-2025, 2025
Short summary
Short summary
We model the cloud condensation nuclei (CCN) activation of sea spray aerosol particles with classical Köhler theory and with a new model approach that takes surface tension lowering into account. We categorize organic compounds into weak, intermediate, and strong surfactants, and we outline for which composition surface tension lowering is important. The results suggest that surface tension lowering allows sea spray aerosol particles in the Aitken mode to be a source of CCN in marine updraughts.
Nadja Omanovic, Brigitta Goger, and Ulrike Lohmann
Atmos. Chem. Phys., 24, 14145–14175, https://doi.org/10.5194/acp-24-14145-2024, https://doi.org/10.5194/acp-24-14145-2024, 2024
Short summary
Short summary
We evaluated the numerical weather model ICON in two horizontal resolutions with two bulk microphysics schemes over hilly and complex terrain in Switzerland and Austria, respectively. We focused on the model's ability to simulate mid-level clouds in summer and winter. By combining observational data from two different field campaigns, we show that an increase in the horizontal resolution and a more advanced cloud microphysics scheme is strongly beneficial for cloud representation.
Ulrike Proske, Nils Brüggemann, Jan P. Gärtner, Oliver Gutjahr, Helmuth Haak, Dian Putrasahan, and Karl-Hermann Wieners
EGUsphere, https://doi.org/10.5194/egusphere-2024-3493, https://doi.org/10.5194/egusphere-2024-3493, 2024
Preprint archived
Short summary
Short summary
Climate models contain coding mistakes, which may look mundane, but can affect the results of interconnected and complex models in unforeseen ways. We describe a sea ice bug in the coupled atmosphere-ocean-sea ice model ICON, giving an example of visual and concise bug communication. This bug represents a novel species of resolution-dependent bugs. The case illustrates the value of open documentation of bugs in climate models and to encourage our community to adopt a similar approach.
Franziska Vogel, Michael P. Adams, Larissa Lacher, Polly B. Foster, Grace C. E. Porter, Barbara Bertozzi, Kristina Höhler, Julia Schneider, Tobias Schorr, Nsikanabasi S. Umo, Jens Nadolny, Zoé Brasseur, Paavo Heikkilä, Erik S. Thomson, Nicole Büttner, Martin I. Daily, Romy Fösig, Alexander D. Harrison, Jorma Keskinen, Ulrike Proske, Jonathan Duplissy, Markku Kulmala, Tuukka Petäjä, Ottmar Möhler, and Benjamin J. Murray
Atmos. Chem. Phys., 24, 11737–11757, https://doi.org/10.5194/acp-24-11737-2024, https://doi.org/10.5194/acp-24-11737-2024, 2024
Short summary
Short summary
Primary ice formation in clouds strongly influences their properties; hence, it is important to understand the sources of ice-nucleating particles (INPs) and their variability. We present 2 months of INP measurements in a Finnish boreal forest using a new semi-autonomous INP counting device based on gas expansion. These results show strong variability in INP concentrations, and we present a case that the INPs we observe are, at least some of the time, of biological origin.
Emilie Fons, Ann Kristin Naumann, David Neubauer, Theresa Lang, and Ulrike Lohmann
Atmos. Chem. Phys., 24, 8653–8675, https://doi.org/10.5194/acp-24-8653-2024, https://doi.org/10.5194/acp-24-8653-2024, 2024
Short summary
Short summary
Aerosols can modify the liquid water path (LWP) of stratocumulus and, thus, their radiative effect. We compare storm-resolving model and satellite data that disagree on the sign of LWP adjustments and diagnose this discrepancy with causal inference. We find that strong precipitation, the absence of wet scavenging, and cloud deepening under a weak inversion contribute to positive LWP adjustments to aerosols in the model, despite weak negative effects from cloud-top entrainment enhancement.
Alkiviadis Kalisoras, Aristeidis K. Georgoulias, Dimitris Akritidis, Robert J. Allen, Vaishali Naik, Chaincy Kuo, Sophie Szopa, Pierre Nabat, Dirk Olivié, Twan van Noije, Philippe Le Sager, David Neubauer, Naga Oshima, Jane Mulcahy, Larry W. Horowitz, and Prodromos Zanis
Atmos. Chem. Phys., 24, 7837–7872, https://doi.org/10.5194/acp-24-7837-2024, https://doi.org/10.5194/acp-24-7837-2024, 2024
Short summary
Short summary
Effective radiative forcing (ERF) is a metric for estimating how human activities and natural agents change the energy flow into and out of the Earth’s climate system. We investigate the anthropogenic aerosol ERF, and we estimate the contribution of individual processes to the total ERF using simulations from Earth system models within the Coupled Model Intercomparison Project Phase 6 (CMIP6). Our findings highlight that aerosol–cloud interactions drive ERF variability during the last 150 years.
Johannes Mülmenstädt, Edward Gryspeerdt, Sudhakar Dipu, Johannes Quaas, Andrew S. Ackerman, Ann M. Fridlind, Florian Tornow, Susanne E. Bauer, Andrew Gettelman, Yi Ming, Youtong Zheng, Po-Lun Ma, Hailong Wang, Kai Zhang, Matthew W. Christensen, Adam C. Varble, L. Ruby Leung, Xiaohong Liu, David Neubauer, Daniel G. Partridge, Philip Stier, and Toshihiko Takemura
Atmos. Chem. Phys., 24, 7331–7345, https://doi.org/10.5194/acp-24-7331-2024, https://doi.org/10.5194/acp-24-7331-2024, 2024
Short summary
Short summary
Human activities release copious amounts of small particles called aerosols into the atmosphere. These particles change how much sunlight clouds reflect to space, an important human perturbation of the climate, whose magnitude is highly uncertain. We found that the latest climate models show a negative correlation but a positive causal relationship between aerosols and cloud water. This means we need to be very careful when we interpret observational studies that can only see correlation.
Fangxuan Ren, Jintai Lin, Chenghao Xu, Jamiu A. Adeniran, Jingxu Wang, Randall V. Martin, Aaron van Donkelaar, Melanie S. Hammer, Larry W. Horowitz, Steven T. Turnock, Naga Oshima, Jie Zhang, Susanne Bauer, Kostas Tsigaridis, Øyvind Seland, Pierre Nabat, David Neubauer, Gary Strand, Twan van Noije, Philippe Le Sager, and Toshihiko Takemura
Geosci. Model Dev., 17, 4821–4836, https://doi.org/10.5194/gmd-17-4821-2024, https://doi.org/10.5194/gmd-17-4821-2024, 2024
Short summary
Short summary
We evaluate the performance of 14 CMIP6 ESMs in simulating total PM2.5 and its 5 components over China during 2000–2014. PM2.5 and its components are underestimated in almost all models, except that black carbon (BC) and sulfate are overestimated in two models, respectively. The underestimation is the largest for organic carbon (OC) and the smallest for BC. Models reproduce the observed spatial pattern for OC, sulfate, nitrate and ammonium well, yet the agreement is poorer for BC.
Nadja Omanovic, Sylvaine Ferrachat, Christopher Fuchs, Jan Henneberger, Anna J. Miller, Kevin Ohneiser, Fabiola Ramelli, Patric Seifert, Robert Spirig, Huiying Zhang, and Ulrike Lohmann
Atmos. Chem. Phys., 24, 6825–6844, https://doi.org/10.5194/acp-24-6825-2024, https://doi.org/10.5194/acp-24-6825-2024, 2024
Short summary
Short summary
We present simulations with a high-resolution numerical weather prediction model to study the growth of ice crystals in low clouds following glaciogenic seeding. We show that the simulated ice crystals grow slower than observed and do not consume as many cloud droplets as measured in the field. This may have implications for forecasting precipitation, as the ice phase is crucial for precipitation at middle and high latitudes.
Ulrike Proske, Sylvaine Ferrachat, and Ulrike Lohmann
Atmos. Chem. Phys., 24, 5907–5933, https://doi.org/10.5194/acp-24-5907-2024, https://doi.org/10.5194/acp-24-5907-2024, 2024
Short summary
Short summary
Climate models include treatment of aerosol particles because these influence clouds and radiation. Over time their representation has grown increasingly detailed. This complexity may hinder our understanding of model behaviour. Thus here we simplify the aerosol representation of our climate model by prescribing mean concentrations, which saves run time and helps to discover unexpected model behaviour. We conclude that simplifications provide a new perspective for model study and development.
Zane Dedekind, Ulrike Proske, Sylvaine Ferrachat, Ulrike Lohmann, and David Neubauer
Atmos. Chem. Phys., 24, 5389–5404, https://doi.org/10.5194/acp-24-5389-2024, https://doi.org/10.5194/acp-24-5389-2024, 2024
Short summary
Short summary
Ice particles precipitating into lower clouds from an upper cloud, the seeder–feeder process, can enhance precipitation. A numerical modeling study conducted in the Swiss Alps found that 48 % of observed clouds were overlapping, with the seeder–feeder process occurring in 10 % of these clouds. Inhibiting the seeder–feeder process reduced the surface precipitation and ice particle growth rates, which were further reduced when additional ice multiplication processes were included in the model.
Dominik L. Schumacher, Mariam Zachariah, Friederike Otto, Clair Barnes, Sjoukje Philip, Sarah Kew, Maja Vahlberg, Roop Singh, Dorothy Heinrich, Julie Arrighi, Maarten van Aalst, Mathias Hauser, Martin Hirschi, Verena Bessenbacher, Lukas Gudmundsson, Hiroko K. Beaudoing, Matthew Rodell, Sihan Li, Wenchang Yang, Gabriel A. Vecchi, Luke J. Harrington, Flavio Lehner, Gianpaolo Balsamo, and Sonia I. Seneviratne
Earth Syst. Dynam., 15, 131–154, https://doi.org/10.5194/esd-15-131-2024, https://doi.org/10.5194/esd-15-131-2024, 2024
Short summary
Short summary
The 2022 summer was accompanied by widespread soil moisture deficits, including an unprecedented drought in Europe. Combining several observation-based estimates and models, we find that such an event has become at least 5 and 20 times more likely due to human-induced climate change in western Europe and the northern extratropics, respectively. Strong regional warming fuels soil desiccation; hence, projections indicate even more potent future droughts as we progress towards a 2 °C warmer world.
George Jordan, Florent Malavelle, Ying Chen, Amy Peace, Eliza Duncan, Daniel G. Partridge, Paul Kim, Duncan Watson-Parris, Toshihiko Takemura, David Neubauer, Gunnar Myhre, Ragnhild Skeie, Anton Laakso, and James Haywood
Atmos. Chem. Phys., 24, 1939–1960, https://doi.org/10.5194/acp-24-1939-2024, https://doi.org/10.5194/acp-24-1939-2024, 2024
Short summary
Short summary
The 2014–15 Holuhraun eruption caused a huge aerosol plume in an otherwise unpolluted region, providing a chance to study how aerosol alters cloud properties. This two-part study uses observations and models to quantify this relationship’s impact on the Earth’s energy budget. Part 1 suggests the models capture the observed spatial and chemical evolution of the plume, yet no model plume is exact. Understanding these differences is key for Part 2, where changes to cloud properties are explored.
Anna J. Miller, Fabiola Ramelli, Christopher Fuchs, Nadja Omanovic, Robert Spirig, Huiying Zhang, Ulrike Lohmann, Zamin A. Kanji, and Jan Henneberger
Atmos. Meas. Tech., 17, 601–625, https://doi.org/10.5194/amt-17-601-2024, https://doi.org/10.5194/amt-17-601-2024, 2024
Short summary
Short summary
We present a method for aerosol and cloud research using two uncrewed aerial vehicles (UAVs). The UAVs have a propeller heating mechanism that allows flights in icing conditions, which has so far been a limitation for cloud research with UAVs. One UAV burns seeding flares, producing a plume of particles that causes ice formation in supercooled clouds. The second UAV measures aerosol size distributions and is used for measuring the seeding plume or for characterizing the boundary layer.
Guangyu Li, Elise K. Wilbourn, Zezhen Cheng, Jörg Wieder, Allison Fagerson, Jan Henneberger, Ghislain Motos, Rita Traversi, Sarah D. Brooks, Mauro Mazzola, Swarup China, Athanasios Nenes, Ulrike Lohmann, Naruki Hiranuma, and Zamin A. Kanji
Atmos. Chem. Phys., 23, 10489–10516, https://doi.org/10.5194/acp-23-10489-2023, https://doi.org/10.5194/acp-23-10489-2023, 2023
Short summary
Short summary
In this work, we present results from an Arctic field campaign (NASCENT) in Ny-Ålesund, Svalbard, on the abundance, variability, physicochemical properties, and potential sources of ice-nucleating particles (INPs) relevant for mixed-phase cloud formation. This work improves the data coverage of Arctic INPs and aerosol properties, allowing for the validation of models predicting cloud microphysical and radiative properties of mixed-phase clouds in the rapidly warming Arctic.
Bernhard M. Enz, Jan P. Engelmann, and Ulrike Lohmann
Geosci. Model Dev., 16, 5093–5112, https://doi.org/10.5194/gmd-16-5093-2023, https://doi.org/10.5194/gmd-16-5093-2023, 2023
Short summary
Short summary
An algorithm to track tropical cyclones in model simulation data has been developed. The algorithm uses many combinations of varying parameter thresholds to detect weaker phases of tropical cyclones while still being resilient to false positives. It is shown that the algorithm performs well and adequately represents the tropical cyclone activity of the underlying simulation data. The impact of false positives on overall tropical cyclone activity is shown to be insignificant.
Colin Tully, David Neubauer, Diego Villanueva, and Ulrike Lohmann
Atmos. Chem. Phys., 23, 7673–7698, https://doi.org/10.5194/acp-23-7673-2023, https://doi.org/10.5194/acp-23-7673-2023, 2023
Short summary
Short summary
This study details the first attempt with a GCM to simulate a fully prognostic aerosol species specifically for cirrus climate intervention. The new approach is in line with the real-world delivery mechanism via aircraft. However, to achieve an appreciable signal from seeding, smaller particles were needed, and their mass emissions needed to be scaled by at least a factor of 100. These biases contributed to either overseeding or small and insignificant effects in response to seeding cirrus.
Colin Tully, David Neubauer, and Ulrike Lohmann
Geosci. Model Dev., 16, 2957–2973, https://doi.org/10.5194/gmd-16-2957-2023, https://doi.org/10.5194/gmd-16-2957-2023, 2023
Short summary
Short summary
A new method to simulate deterministic ice nucleation processes based on the differential activated fraction was evaluated against a cumulative approach. Box model simulations of heterogeneous-only ice nucleation within cirrus suggest that the latter approach likely underpredicts the ice crystal number concentration. Longer simulations with a GCM show that choosing between these two approaches impacts ice nucleation competition within cirrus but leads to small and insignificant climate effects.
Zane Dedekind, Jacopo Grazioli, Philip H. Austin, and Ulrike Lohmann
Atmos. Chem. Phys., 23, 2345–2364, https://doi.org/10.5194/acp-23-2345-2023, https://doi.org/10.5194/acp-23-2345-2023, 2023
Short summary
Short summary
Simulations allowing ice particles to collide with one another producing more ice particles represented surface observations of ice particles accurately. An increase in ice particles formed through collisions was related to sharp changes in the wind direction and speed with height. Changes in wind speed and direction can therefore cause more enhanced collisions between ice particles and alter how fast and how much precipitation forms. Simulations were conducted with the atmospheric model COSMO.
Julie Thérèse Pasquier, Jan Henneberger, Fabiola Ramelli, Annika Lauber, Robert Oscar David, Jörg Wieder, Tim Carlsen, Rosa Gierens, Marion Maturilli, and Ulrike Lohmann
Atmos. Chem. Phys., 22, 15579–15601, https://doi.org/10.5194/acp-22-15579-2022, https://doi.org/10.5194/acp-22-15579-2022, 2022
Short summary
Short summary
It is important to understand how ice crystals and cloud droplets form in clouds, as their concentrations and sizes determine the exact radiative properties of the clouds. Normally, ice crystals form from aerosols, but we found evidence for the formation of additional ice crystals from the original ones over a large temperature range within Arctic clouds. In particular, additional ice crystals were formed during collisions of several ice crystals or during the freezing of large cloud droplets.
Florin N. Isenrich, Nadia Shardt, Michael Rösch, Julia Nette, Stavros Stavrakis, Claudia Marcolli, Zamin A. Kanji, Andrew J. deMello, and Ulrike Lohmann
Atmos. Meas. Tech., 15, 5367–5381, https://doi.org/10.5194/amt-15-5367-2022, https://doi.org/10.5194/amt-15-5367-2022, 2022
Short summary
Short summary
Ice nucleation in the atmosphere influences cloud properties and lifetimes. Microfluidic instruments have recently been used to investigate ice nucleation, but these instruments are typically made out of a polymer that contributes to droplet instability over extended timescales and relatively high temperature uncertainty. To address these drawbacks, we develop and validate a new microfluidic instrument that uses fluoropolymer tubing to extend droplet stability and improve temperature accuracy.
Colin Tully, David Neubauer, Nadja Omanovic, and Ulrike Lohmann
Atmos. Chem. Phys., 22, 11455–11484, https://doi.org/10.5194/acp-22-11455-2022, https://doi.org/10.5194/acp-22-11455-2022, 2022
Short summary
Short summary
The proposed geoengineering method, cirrus cloud thinning, was evaluated using a more physically based microphysics scheme coupled to a more realistic approach for calculating ice cloud fractions in the ECHAM-HAM GCM. Sensitivity tests reveal that using the new ice cloud fraction approach and increasing the critical ice saturation ratio for ice nucleation on seeding particles reduces warming from overseeding. However, this geoengineering method is unlikely to be feasible on a global scale.
Qirui Zhong, Nick Schutgens, Guido van der Werf, Twan van Noije, Kostas Tsigaridis, Susanne E. Bauer, Tero Mielonen, Alf Kirkevåg, Øyvind Seland, Harri Kokkola, Ramiro Checa-Garcia, David Neubauer, Zak Kipling, Hitoshi Matsui, Paul Ginoux, Toshihiko Takemura, Philippe Le Sager, Samuel Rémy, Huisheng Bian, Mian Chin, Kai Zhang, Jialei Zhu, Svetlana G. Tsyro, Gabriele Curci, Anna Protonotariou, Ben Johnson, Joyce E. Penner, Nicolas Bellouin, Ragnhild B. Skeie, and Gunnar Myhre
Atmos. Chem. Phys., 22, 11009–11032, https://doi.org/10.5194/acp-22-11009-2022, https://doi.org/10.5194/acp-22-11009-2022, 2022
Short summary
Short summary
Aerosol optical depth (AOD) errors for biomass burning aerosol (BBA) are evaluated in 18 global models against satellite datasets. Notwithstanding biases in satellite products, they allow model evaluations. We observe large and diverse model biases due to errors in BBA. Further interpretations of AOD diversities suggest large biases exist in key processes for BBA which require better constraining. These results can contribute to further model improvement and development.
Jörg Wieder, Nikola Ihn, Claudia Mignani, Moritz Haarig, Johannes Bühl, Patric Seifert, Ronny Engelmann, Fabiola Ramelli, Zamin A. Kanji, Ulrike Lohmann, and Jan Henneberger
Atmos. Chem. Phys., 22, 9767–9797, https://doi.org/10.5194/acp-22-9767-2022, https://doi.org/10.5194/acp-22-9767-2022, 2022
Short summary
Short summary
Ice formation and its evolution in mixed-phase clouds are still uncertain. We evaluate the lidar retrieval of ice-nucleating particle concentration in dust-dominated and continental air masses over the Swiss Alps with in situ observations. A calibration factor to improve the retrieval from continental air masses is proposed. Ice multiplication factors are obtained with a new method utilizing remote sensing. Our results indicate that secondary ice production occurs at temperatures down to −30 °C.
Verena Bessenbacher, Sonia Isabelle Seneviratne, and Lukas Gudmundsson
Geosci. Model Dev., 15, 4569–4596, https://doi.org/10.5194/gmd-15-4569-2022, https://doi.org/10.5194/gmd-15-4569-2022, 2022
Short summary
Short summary
Earth observations have many missing values. They are often filled using information from spatial and temporal contexts that mostly ignore information from related observed variables. We propose the gap-filling method CLIMFILL that additionally uses information from related variables. We test CLIMFILL using gap-free reanalysis data of variables related to soil–moisture climate interactions. CLIMFILL creates estimates for the missing values that recover the original dependence structure.
Zoé Brasseur, Dimitri Castarède, Erik S. Thomson, Michael P. Adams, Saskia Drossaart van Dusseldorp, Paavo Heikkilä, Kimmo Korhonen, Janne Lampilahti, Mikhail Paramonov, Julia Schneider, Franziska Vogel, Yusheng Wu, Jonathan P. D. Abbatt, Nina S. Atanasova, Dennis H. Bamford, Barbara Bertozzi, Matthew Boyer, David Brus, Martin I. Daily, Romy Fösig, Ellen Gute, Alexander D. Harrison, Paula Hietala, Kristina Höhler, Zamin A. Kanji, Jorma Keskinen, Larissa Lacher, Markus Lampimäki, Janne Levula, Antti Manninen, Jens Nadolny, Maija Peltola, Grace C. E. Porter, Pyry Poutanen, Ulrike Proske, Tobias Schorr, Nsikanabasi Silas Umo, János Stenszky, Annele Virtanen, Dmitri Moisseev, Markku Kulmala, Benjamin J. Murray, Tuukka Petäjä, Ottmar Möhler, and Jonathan Duplissy
Atmos. Chem. Phys., 22, 5117–5145, https://doi.org/10.5194/acp-22-5117-2022, https://doi.org/10.5194/acp-22-5117-2022, 2022
Short summary
Short summary
The present measurement report introduces the ice nucleation campaign organized in Hyytiälä, Finland, in 2018 (HyICE-2018). We provide an overview of the campaign settings, and we describe the measurement infrastructure and operating procedures used. In addition, we use results from ice nucleation instrument inter-comparison to show that the suite of these instruments deployed during the campaign reports consistent results.
Ulrike Proske, Sylvaine Ferrachat, David Neubauer, Martin Staab, and Ulrike Lohmann
Atmos. Chem. Phys., 22, 4737–4762, https://doi.org/10.5194/acp-22-4737-2022, https://doi.org/10.5194/acp-22-4737-2022, 2022
Short summary
Short summary
Cloud microphysical processes shape cloud properties and are therefore important to represent in climate models. Their parameterization has grown more complex, making the model results more difficult to interpret. Using sensitivity analysis we test how the global aerosol–climate model ECHAM-HAM reacts to changes to these parameterizations. The model is sensitive to the parameterization of ice crystal autoconversion but not to, e.g., self-collection, suggesting that it may be simplified.
Jörg Wieder, Claudia Mignani, Mario Schär, Lucie Roth, Michael Sprenger, Jan Henneberger, Ulrike Lohmann, Cyril Brunner, and Zamin A. Kanji
Atmos. Chem. Phys., 22, 3111–3130, https://doi.org/10.5194/acp-22-3111-2022, https://doi.org/10.5194/acp-22-3111-2022, 2022
Short summary
Short summary
We investigate the variation in ice-nucleating particles (INPs) relevant for primary ice formation in mixed-phased clouds over the Alps based on simultaneous in situ observations at a mountaintop and a nearby high valley (1060 m height difference). In most cases, advection from the surrounding lower regions was responsible for changes in INP concentration, causing a diurnal cycle at the mountaintop. Our study underlines the importance of the planetary boundary layer as an INP reserve.
Zane Dedekind, Annika Lauber, Sylvaine Ferrachat, and Ulrike Lohmann
Atmos. Chem. Phys., 21, 15115–15134, https://doi.org/10.5194/acp-21-15115-2021, https://doi.org/10.5194/acp-21-15115-2021, 2021
Short summary
Short summary
The RACLETS campaign combined cloud and snow research to improve the understanding of precipitation formation in clouds. A numerical weather prediction model, COSMO, was used to assess the importance of ice crystal enhancement by ice–ice collisions for cloud properties. We found that the number of ice crystals increased by 1 to 3 orders of magnitude when ice–ice collisions were permitted to occur, reducing localized regions of high precipitation and, thereby, improving the model performance.
Paolo Pelucchi, David Neubauer, and Ulrike Lohmann
Geosci. Model Dev., 14, 5413–5434, https://doi.org/10.5194/gmd-14-5413-2021, https://doi.org/10.5194/gmd-14-5413-2021, 2021
Short summary
Short summary
Stratocumulus are thin clouds whose cloud cover is underestimated in climate models partly due to overly low vertical resolution. We develop a scheme that locally refines the vertical grid based on a physical constraint for the cloud top. Global simulations show that the scheme, implemented only in the radiation routine, can increase stratocumulus cloud cover. However, this effect is poorly propagated to the simulated cloud cover. The scheme's limitations and possible ways forward are discussed.
Paraskevi Georgakaki, Aikaterini Bougiatioti, Jörg Wieder, Claudia Mignani, Fabiola Ramelli, Zamin A. Kanji, Jan Henneberger, Maxime Hervo, Alexis Berne, Ulrike Lohmann, and Athanasios Nenes
Atmos. Chem. Phys., 21, 10993–11012, https://doi.org/10.5194/acp-21-10993-2021, https://doi.org/10.5194/acp-21-10993-2021, 2021
Short summary
Short summary
Aerosol and cloud observations coupled with a droplet activation parameterization was used to investigate the aerosol–cloud droplet link in alpine mixed-phase clouds. Predicted droplet number, Nd, agrees with observations and never exceeds a characteristic “limiting droplet number”, Ndlim, which depends solely on σw. Nd becomes velocity limited when it is within 50 % of Ndlim. Identifying when dynamical changes control Nd variability is central for understanding aerosol–cloud interactions.
Fabiola Ramelli, Jan Henneberger, Robert O. David, Johannes Bühl, Martin Radenz, Patric Seifert, Jörg Wieder, Annika Lauber, Julie T. Pasquier, Ronny Engelmann, Claudia Mignani, Maxime Hervo, and Ulrike Lohmann
Atmos. Chem. Phys., 21, 6681–6706, https://doi.org/10.5194/acp-21-6681-2021, https://doi.org/10.5194/acp-21-6681-2021, 2021
Short summary
Short summary
Orographic mixed-phase clouds are an important source of precipitation, but the ice formation processes within them remain uncertain. Here we investigate the origin of ice crystals in a mixed-phase cloud in the Swiss Alps using aerosol and cloud data from in situ and remote sensing observations. We found that ice formation primarily occurs in cloud top generating cells. Our results indicate that secondary ice processes are active in the feeder region, which can enhance orographic precipitation.
Fabiola Ramelli, Jan Henneberger, Robert O. David, Annika Lauber, Julie T. Pasquier, Jörg Wieder, Johannes Bühl, Patric Seifert, Ronny Engelmann, Maxime Hervo, and Ulrike Lohmann
Atmos. Chem. Phys., 21, 5151–5172, https://doi.org/10.5194/acp-21-5151-2021, https://doi.org/10.5194/acp-21-5151-2021, 2021
Short summary
Short summary
Interactions between dynamics, microphysics and orography can enhance precipitation. Yet the exact role of these interactions is still uncertain. Here we investigate the role of low-level blocking and turbulence for precipitation by combining remote sensing and in situ observations. The observations show that blocked flow can induce the formation of feeder clouds and that turbulence can enhance hydrometeor growth, demonstrating the importance of local flow effects for orographic precipitation.
Annika Lauber, Jan Henneberger, Claudia Mignani, Fabiola Ramelli, Julie T. Pasquier, Jörg Wieder, Maxime Hervo, and Ulrike Lohmann
Atmos. Chem. Phys., 21, 3855–3870, https://doi.org/10.5194/acp-21-3855-2021, https://doi.org/10.5194/acp-21-3855-2021, 2021
Short summary
Short summary
An accurate prediction of the ice crystal number concentration (ICNC) is important to determine the radiation budget, lifetime, and precipitation formation of clouds. Even though secondary-ice processes can increase the ICNC by several orders of magnitude, they are poorly constrained and lack a well-founded quantification. During measurements on a mountain slope, a high ICNC of small ice crystals was observed just below 0 °C, attributed to a secondary-ice process and parametrized in this study.
Jonas Gliß, Augustin Mortier, Michael Schulz, Elisabeth Andrews, Yves Balkanski, Susanne E. Bauer, Anna M. K. Benedictow, Huisheng Bian, Ramiro Checa-Garcia, Mian Chin, Paul Ginoux, Jan J. Griesfeller, Andreas Heckel, Zak Kipling, Alf Kirkevåg, Harri Kokkola, Paolo Laj, Philippe Le Sager, Marianne Tronstad Lund, Cathrine Lund Myhre, Hitoshi Matsui, Gunnar Myhre, David Neubauer, Twan van Noije, Peter North, Dirk J. L. Olivié, Samuel Rémy, Larisa Sogacheva, Toshihiko Takemura, Kostas Tsigaridis, and Svetlana G. Tsyro
Atmos. Chem. Phys., 21, 87–128, https://doi.org/10.5194/acp-21-87-2021, https://doi.org/10.5194/acp-21-87-2021, 2021
Short summary
Short summary
Simulated aerosol optical properties as well as the aerosol life cycle are investigated for 14 global models participating in the AeroCom initiative. Considerable diversity is found in the simulated aerosol species emissions and lifetimes, also resulting in a large diversity in the simulated aerosol mass, composition, and optical properties. A comparison with observations suggests that, on average, current models underestimate the direct effect of aerosol on the atmosphere radiation budget.
Steven T. Turnock, Robert J. Allen, Martin Andrews, Susanne E. Bauer, Makoto Deushi, Louisa Emmons, Peter Good, Larry Horowitz, Jasmin G. John, Martine Michou, Pierre Nabat, Vaishali Naik, David Neubauer, Fiona M. O'Connor, Dirk Olivié, Naga Oshima, Michael Schulz, Alistair Sellar, Sungbo Shim, Toshihiko Takemura, Simone Tilmes, Kostas Tsigaridis, Tongwen Wu, and Jie Zhang
Atmos. Chem. Phys., 20, 14547–14579, https://doi.org/10.5194/acp-20-14547-2020, https://doi.org/10.5194/acp-20-14547-2020, 2020
Short summary
Short summary
A first assessment is made of the historical and future changes in air pollutants from models participating in the 6th Coupled Model Intercomparison Project (CMIP6). Substantial benefits to future air quality can be achieved in future scenarios that implement measures to mitigate climate and involve reductions in air pollutant emissions, particularly methane. However, important differences are shown between models in the future regional projection of air pollutants under the same scenario.
Augustin Mortier, Jonas Gliß, Michael Schulz, Wenche Aas, Elisabeth Andrews, Huisheng Bian, Mian Chin, Paul Ginoux, Jenny Hand, Brent Holben, Hua Zhang, Zak Kipling, Alf Kirkevåg, Paolo Laj, Thibault Lurton, Gunnar Myhre, David Neubauer, Dirk Olivié, Knut von Salzen, Ragnhild Bieltvedt Skeie, Toshihiko Takemura, and Simone Tilmes
Atmos. Chem. Phys., 20, 13355–13378, https://doi.org/10.5194/acp-20-13355-2020, https://doi.org/10.5194/acp-20-13355-2020, 2020
Short summary
Short summary
We present a multiparameter analysis of the aerosol trends over the last 2 decades in the different regions of the world. In most of the regions, ground-based observations show a decrease in aerosol content in both the total atmospheric column and at the surface. The use of climate models, assessed against these observations, reveals however an increase in the total aerosol load, which is not seen with the sole use of observation due to partial coverage in space and time.
Cited articles
Ansmann, A., Tesche, M., Althausen, D., Müller, D., Seifert, P.,
Freudenthaler, V., Heese, B., Wiegner, M., Pisani, G., Knippertz, P., and
Dubovik, O.: Influence of Saharan Dust on Cloud Glaciation in Southern
Morocco during the Saharan Mineral Dust Experiment, J.
Geophys. Res., 113, D04210, https://doi.org/10.1029/2007JD008785, 2008. a
Ansmann, A., Tesche, M., Seifert, P., Althausen, D., Engelmann, R., Fruntke,
J., Wandinger, U., Mattis, I., and Müller, D.: Evolution of the Ice Phase
in Tropical Altocumulus: SAMUM Lidar Observations over Cape Verde,
J. Geophys. Res., 114, D17208, https://doi.org/10.1029/2008JD011659, 2009. a, b, c
Bergeron, T.: On the physics of cloud and precipitation: Mémoire présenté a L'association de Météorologie de L'U.G.G.I., Lisbonne, September 1933, Paris, France, Imprimerie Paul Dupont, 1935. a
Boucher, O., Randall, D., Artaxo, P., Bretherton, C., Feingold, G., Forster,
P., Kerminen, V.-M., Kondo, Y., Liao, H., Lohmann, U., Rasch, P., Satheesh,
S. K., Sherwood, S., Stevens, B., and Zhang, X. Y.: Clouds and Aerosols,
in: Climate Change 2013: The Physical Science Basis. Contribution
of Working Group I to the Fifth Assessment Report of the
Intergovernmental Panel on Climate Change, Cambridge University
Press, Cambridge, United Kingdom and New York, NY, USA, 2013. a
Carruthers, D. J. and Choularton, T. W.: A Model of the Feeder-Seeder Mechanism
of Orographic Rain Including Stratification and Wind-Drift Effects, Q.
J. Roy. Meteor. Soc., 109, 575–588,
https://doi.org/10.1002/qj.49710946109, 1983. a
Cazenave, Q., Ceccaldi, M., Delanoë, J., Pelon, J., Groß, S., and Heymsfield, A.: Evolution of DARDAR-CLOUD ice cloud retrievals: new parameters and impacts on the retrieved microphysical properties, Atmos. Meas. Tech., 12, 2819–2835, https://doi.org/10.5194/amt-12-2819-2019, 2019. a, b
CDS (Copernicus Climate Change Service) (2017): ERA5: fifth generation of ECMWF atmospheric reanalyses of the global climate, Copernicus Climate Change Service Climate Data Store (CDS), available at: https://cds.climate.copernicus.eu/#!/home (last access: 7 November 2019), 2017. a
Ceccaldi, M., Delanoë, J., Hogan, R. J., Pounder, N. L., Protat, A., and
Pelon, J.: From CloudSat-CALIPSO to EarthCare: Evolution of
the DARDAR Cloud Classification and Its Comparison to Airborne
Radar-Lidar Observations, J. Geophys. Res.-Atmos., 118,
7962–7981, https://doi.org/10.1002/jgrd.50579, 2013. a, b, c
Cess, R. D., Potter, G. L., Blanchet, J. P., Boer, G. J., Del Genio, A. D.,
Déqué, M., Dymnikov, V., Galin, V., Gates, W. L., Ghan, S. J., Kiehl,
J. T., Lacis, A. A., Le Treut, H., Li, Z.-X., Liang, X.-Z., McAvaney, B. J.,
Meleshko, V. P., Mitchell, J. F. B., Morcrette, J.-J., Randall, D. A., Rikus,
L., Roeckner, E., Royer, J. F., Schlese, U., Sheinin, D. A., Slingo, A.,
Sokolov, A. P., Taylor, K. E., Washington, W. M., Wetherald, R. T., Yagai,
I., and Zhang, M.-H.: Intercomparison and Interpretation of Climate Feedback
Processes in 19 Atmospheric General Circulation Models, J.
Geophys. Res., 95, 16601–16615, https://doi.org/10.1029/JD095iD10p16601,
1990. a
Chan, M. A. and Comiso, J. C.: Cloud Features Detected by MODIS but Not by
CloudSat and CALIOP: CLOUDS UNDETECTED BY CLOUDSAT AND CALIOP,
Geophys. Res. Lett., 38, L24813, https://doi.org/10.1029/2011GL050063, 2011. a
Chen, Y.-S., Harrington, J. Y., Verlinde, J., Zhang, F., and Oue, M.: Dynamical
Response of an Arctic Mixed-Phase Cloud to Ice Precipitation
and Downwelling Longwave Radiation From an Upper-Level Cloud,
J. Geophys. Res.-Atmos., 125, e2019JD031089,
https://doi.org/10.1029/2019JD031089, 2020. a
Chepfer, H., Bony, S., Winker, D., Cesana, G., Dufresne, J. L., Minnis, P.,
Stubenrauch, C. J., and Zeng, S.: The GCM-Oriented CALIPSO Cloud
Product (CALIPSO-GOCCP), J. Geophys. Res., 115,
D00H16, https://doi.org/10.1029/2009JD012251, 2010. a, b
Chepfer, H., Cesana, G., Winker, D., Getzewich, B., Vaughan, M., and Liu, Z.:
Comparison of Two Different Cloud Climatologies Derived from
CALIOP-Attenuated Backscattered Measurements (Level 1): The
CALIPSO-ST and the CALIPSO-GOCCP, J. Atmos. Ocean. Tech., 30, 725–744,
https://doi.org/10.1175/JTECH-D-12-00057.1, 2013. a, b
Chiruta, M. and Wang, P. K.: The Capacitance of Rosette Ice Crystals,
J. Atmos. Sci., 60, 836–846, 2003. a
Choularton, T. W. and Perry, S. J.: A Model of the Orographic Enhancement of
Snowfall by the Seeder-Feeder Mechanism, Q. J. Roy.
Meteor. Soc., 112, 335–345, https://doi.org/10.1002/qj.49711247204, 1986. a
Christensen, M. W., Carrió, G. G., Stephens, G. L., and Cotton, W. R.:
Radiative Impacts of Free-Tropospheric Clouds on the
Properties of Marine Stratocumulus, J. Atmos.
Sci., 70, 3102–3118, https://doi.org/10.1175/JAS-D-12-0287.1, 2013. a
CloudSat radar status: CloudSat Radar Status, available at:
https://cloudsat.atmos.colostate.edu/news/CloudSat_status, last access: 18 August 2020. a
Creamean, J. M., Suski, K. J., Rosenfeld, D., Cazorla, A., DeMott, P. J.,
Sullivan, R. C., White, A. B., Ralph, F. M., Minnis, P., Comstock, J. M.,
Tomlinson, J. M., and Prather, K. A.: Dust and Biological Aerosols from
the Sahara and Asia Influence Precipitation in the Western
U.S., Science, 339, 1572–1578, https://doi.org/10.1126/science.1227279, 2013. a
Das, S. K., Golhait, R., and Uma, K.: Clouds Vertical Properties over the
Northern Hemisphere Monsoon Regions from CloudSat-CALIPSO
Measurements, Atmos. Res., 183, 73–83,
https://doi.org/10.1016/j.atmosres.2016.08.011, 2017. a
Delanoë, J. and Hogan, R.: DARDAR-CLOUD Documentation, ICARE Data and Services Center, Villeneuve d'Ascq, France,
2010a. a
Delanoë, J. and Hogan, R. J.: A Variational Scheme for Retrieving Ice Cloud
Properties from Combined Radar, Lidar, and Infrared Radiometer, J.
Geophys. Res., 113, D07204, https://doi.org/10.1029/2007JD009000, 2008. a
Delanoë, J. and Hogan, R. J.: Combined CloudSat-CALIPSO-MODIS
Retrievals of the Properties of Ice Clouds, J. Geophys. Res.,
115, D00H29, https://doi.org/10.1029/2009JD012346, 2010b. a, b
Dennis, A. S.: Initiation of Showers by Snow, J. Meteorol., 11,
157–162, 1954. a
Dore, A., Sobik, M., and Migala, K.: Patterns of Precipitation and Pollutant
Deposition in the Western Sudete Mountains, Poland, Atmos.
Environ., 33, 3301–3312, https://doi.org/10.1016/S1352-2310(98)00294-5, 1999. a
Fernández-González, S., Valero, F., Sánchez, J. L., Gascón,
E., López, L., García-Ortega, E., and Merino, A.: Analysis of a
Seeder-Feeder and Freezing Drizzle Event, J. Geophys. Res.-Atmos., 120, 3984–3999, https://doi.org/10.1002/2014JD022916, 2015. a
Findeisen, W.: Kolloid-Meteorologische Vorgänge Bei
Neiderschlagsbildung, Meteorol. Z., 55, 121–133, 1938. a
Fleishauer, R. P., Larson, V. E., and Vonder Haar, T. H.: Observed
Microphysical Structure of Midlevel, Mixed-Phase Clouds,
J. Atmos. Sci., 59, 1779–1804,
https://doi.org/10.1175/1520-0469(2002)059<1779:OMSOMM>2.0.CO;2, 2002. a
Gao, W., Sui, C.-H., and Hu, Z.: A Study of Macrophysical and Microphysical
Properties of Warm Clouds over the Northern Hemisphere Using
CloudSat/CALIPSO Data: Properties of Warm Clouds over NH,
J. Geophys. Res.-Atmos., 119, 3268–3280,
https://doi.org/10.1002/2013JD020948, 2014. a
Gasparini, B., Meyer, A., Neubauer, D., Münch, S., and Lohmann, U.: Cirrus
Cloud Properties as Seen by the CALIPSO Satellite
and ECHAM-HAM Global Climate Model, J. Climate, 31,
1983–2003, https://doi.org/10.1175/JCLI-D-16-0608.1, 2018. a, b, c, d
Grams, C. M., Beerli, R., Pfenninger, S., Staffell, I., and Wernli, H.:
Balancing Europe's Wind-Power Output through Spatial Deployment Informed
by Weather Regimes, Nat. Clim. Change, 7, 557–562,
https://doi.org/10.1038/nclimate3338, 2017. a
Hallett, J. and Mossop, S. C.: Production of Secondary Ice Particles during the
Riming Process, Nature, 249, 26–28, https://doi.org/10.1038/249026a0, 1974. a
Herbert, R. J., Murray, B. J., Dobbie, S. J., and Koop, T.: Sensitivity of
Liquid Clouds to Homogenous Freezing Parameterizations, Geophys. Res.
Lett., 42, 1599–1605, https://doi.org/10.1002/2014GL062729, 2015. a
Hersbach, H., Bell, B., Berrisford, P., Hirahara, S., Horányi, A.,
Muñoz-Sabater, J., Nicolas, J., Peubey, C., Radu, R., Schepers, D.,
Simmons, A., Soci, C., Abdalla, S., Abellan, X., Balsamo, G., Bechtold, P.,
Biavati, G., Bidlot, J., Bonavita, M., Chiara, G., Dahlgren, P., Dee, D.,
Diamantakis, M., Dragani, R., Flemming, J., Forbes, R., Fuentes, M., Geer,
A., Haimberger, L., Healy, S., Hogan, R. J., Hólm, E., Janisková, M.,
Keeley, S., Laloyaux, P., Lopez, P., Lupu, C., Radnoti, G., Rosnay, P.,
Rozum, I., Vamborg, F., Villaume, S., and Thépaut, J.-N.: The ERA5
Global Reanalysis, Q. J. Roy. Meteor. Soc.,
146, 1999–2049, https://doi.org/10.1002/qj.3803, 2020. a
Heymsfield, A. J., Schmitt, C., and Bansemer, A.: Ice Cloud Particle Size
Distributions and Pressure-Dependent Terminal Velocities from In
Situ Observations at Temperatures from 0∘ to
−86 ∘C, J. Atmos. Sci., 70, 4123–4154,
https://doi.org/10.1175/JAS-D-12-0124.1, 2013. a
Hill, F. F., Browning, K. A., and Bader, M. J.: Radar and Raingauge
Observations of Orographic Rain over South Wales, Q. J.
Roy. Meteor. Soc., 107, 643–670,
https://doi.org/10.1002/qj.49710745312, 2007. a
Hitschfeld, W.: Comments on “Cirrus Cloud Seeding as a Trigger for
Storm Development”, J. Atmos. Sci., 25, 530–531,
1968. a
Hobbs, P. V., Matejka, T. J., Herzegh, P. H., Locatelli, J. D., and Houze,
R. A.: The Mesoscale and Microscale Structure and Organization of
Clouds and Precipitation in Midlatitude Cyclones. I: A Case
Study of a Cold Front, J. Atmos. Sci., 37,
568–596, https://doi.org/10.1175/1520-0469(1980)037<0568:TMAMSA>2.0.CO;2, 1980. a, b
Hobbs, P. V., Lyons, J. H., Locatelli, J. D., Biswas, K. R., Radke, L. F.,
Weiss, R. R. S., and Rangno, A. L.: Radar Detection of
Cloud-Seeding Effects, Science, 213, 1250–1252,
https://doi.org/10.1126/science.213.4513.1250, 1981. a
Hobbs, P. V., Rangno, A. L., Shupe, M., and Uttal, T.: Airborne Studies of
Cloud Structures over the Arctic Ocean and Comparisons with Retrievals
from Ship-Based Remote Sensing Measurements, J. Geophys. Res.-Atmos., 106, 15029–15044, https://doi.org/10.1029/2000JD900323, 2001. a
Hong, Y. and Liu, G.: The Characteristics of Ice Cloud Properties
Derived from CloudSat and CALIPSO Measurements, J. Climate,
28, 3880–3901, https://doi.org/10.1175/JCLI-D-14-00666.1, 2015. a, b, c
Kanji, Z. A., Ladino, L. A., Wex, H., Boose, Y., Burkert-Kohn, M., Cziczo,
D. J., and Krämer, M.: Overview of Ice Nucleating Particles,
Meteor. Mon., 58, 1.1–1.33,
https://doi.org/10.1175/AMSMONOGRAPHS-D-16-0006.1, 2017. a, b
Korolev, A. and Leisner, T.: Review of experimental studies of secondary ice production, Atmos. Chem. Phys., 20, 11767–11797, https://doi.org/10.5194/acp-20-11767-2020, 2020. a
Krämer, M., Schiller, C., Afchine, A., Bauer, R., Gensch, I., Mangold, A., Schlicht, S., Spelten, N., Sitnikov, N., Borrmann, S., de Reus, M., and Spichtinger, P.: Ice supersaturations and cirrus cloud crystal numbers, Atmos. Chem. Phys., 9, 3505–3522, https://doi.org/10.5194/acp-9-3505-2009, 2009. a
Krämer, M., Rolf, C., Luebke, A., Afchine, A., Spelten, N., Costa, A., Meyer, J., Zöger, M., Smith, J., Herman, R. L., Buchholz, B., Ebert, V., Baumgardner, D., Borrmann, S., Klingebiel, M., and Avallone, L.: A microphysics guide to cirrus clouds – Part 1: Cirrus types, Atmos. Chem. Phys., 16, 3463–3483, https://doi.org/10.5194/acp-16-3463-2016, 2016. a, b, c, d
Krämer, M., Rolf, C., Spelten, N., Afchine, A., Fahey, D., Jensen, E., Khaykin, S., Kuhn, T., Lawson, P., Lykov, A., Pan, L. L., Riese, M., Rollins, A., Stroh, F., Thornberry, T., Wolf, V., Woods, S., Spichtinger, P., Quaas, J., and Sourdeval, O.: A microphysics guide to cirrus – Part 2: Climatologies of clouds and humidity from observations, Atmos. Chem. Phys., 20, 12569–12608, https://doi.org/10.5194/acp-20-12569-2020, 2020. a, b
Lamb, D. and Verlinde, J.: Physics and Chemistry of Clouds, Cambridge
University Press, Cambridge, https://doi.org/10.1017/CBO9780511976377, 2011. a, b
Lauber, A., Kiselev, A., Pander, T., Handmann, P., and Leisner, T.: Secondary
Ice Formation during Freezing of Levitated Droplets, J.
Atmos. Sci., 75, 2815–2826, https://doi.org/10.1175/JAS-D-18-0052.1,
2018. a
Lawson, R. P., Woods, S., Jensen, E., Erfani, E., Gurganus, C., Gallagher, M.,
Connolly, P., Whiteway, J., Baran, A. J., May, P., Heymsfield, A., Schmitt,
C. G., McFarquhar, G., Um, J., Protat, A., Bailey, M., Lance, S., Muehlbauer,
A., Stith, J., Korolev, A., Toon, O. B., and Krämer, M.: A Review of
Ice Particle Shapes in Cirrus Formed In Situ and in Anvils,
J. Geophys. Res.-Atmos., 124, 10049–10090,
https://doi.org/10.1029/2018JD030122, 2019. a
Libbrecht, K. G.: The Physics of Snow Crystals, Rep. Prog. Phys.,
68, 855–895, https://doi.org/10.1088/0034-4885/68/4/R03, 2005. a, b
Liu, D., Liu, Q., and Zhou, L.: Underestimation of Oceanic Warm Cloud
Occurrences by the Cloud Profiling Radar Aboard CloudSat, J.
Meteorol. Res., 29, 576–593, https://doi.org/10.1007/s13351-015-5027-5, 2015. a
Locatelli, J. D., Hobbs, P. V., and Biswas, K. R.: Precipitation from
Stratocumulus Clouds Affected by Fallstreaks and Artificial
Seeding, J. Clim. Appl. Meteorol., 22, 1393–1403,
https://doi.org/10.1175/1520-0450(1983)022<1393:PFSCAB>2.0.CO;2, 1983. a, b
Lohmann, U. and Neubauer, D.: The importance of mixed-phase and ice clouds for climate sensitivity in the global aerosol–climate model ECHAM6-HAM2, Atmos. Chem. Phys., 18, 8807–8828, https://doi.org/10.5194/acp-18-8807-2018, 2018. a
Luebke, A. E., Avallone, L. M., Schiller, C., Meyer, J., Rolf, C., and Krämer, M.: Ice water content of Arctic, midlatitude, and tropical cirrus – Part 2: Extension of the database and new statistical analysis, Atmos. Chem. Phys., 13, 6447–6459, https://doi.org/10.5194/acp-13-6447-2013, 2013. a, b, c
Luebke, A. E., Afchine, A., Costa, A., Grooß, J.-U., Meyer, J., Rolf, C., Spelten, N., Avallone, L. M., Baumgardner, D., and Krämer, M.: The origin of midlatitude ice clouds and the resulting influence on their microphysical properties, Atmos. Chem. Phys., 16, 5793–5809, https://doi.org/10.5194/acp-16-5793-2016, 2016. a, b, c, d, e, f
Mace, G. G., Zhang, Q., Vaughan, M., Marchand, R., Stephens, G., Trepte, C.,
and Winker, D.: A Description of Hydrometeor Layer Occurrence Statistics
Derived from the First Year of Merged Cloudsat and CALIPSO Data,
J. Geophys. Res., 114, D00A26, https://doi.org/10.1029/2007JD009755, 2009. a, b, c, d, e, f, g, h, i, j, k
Marcolli, C.: Pre-activation of aerosol particles by ice preserved in pores, Atmos. Chem. Phys., 17, 1595–1622, https://doi.org/10.5194/acp-17-1595-2017, 2017. a
Matus, A. V. and L'Ecuyer, T. S.: The Role of Cloud Phase in Earth's
Radiation Budget, J. Geophys. Res.-Atmos., 122,
2559–2578, https://doi.org/10.1002/2016JD025951, 2017. a, b, c, d
Miloshevich, L. M. and Heymsfield, A. J.: A Balloon-Borne Continuous
Cloud Particle Replicator for Measuring Vertical Profiles of Cloud
Microphysical Properties: Instrument Design, Performance, and
Collectoin Efficiency Analysis, J. Atmos. Ocean.
Tech., 14, 753–768, 1997. a
Mitchell, D. L.: Use of Mass- and Area-Dimensional Power Laws for
Determining Precipitation Particle Terminal Velocities, J.
Atmos. Sci., 53, 1710–1723, 1996. a
Mossop, S. C. and Hallett, J.: Ice Crystal Concentration in Cumulus
Clouds: Influence of the Drop Spectrum, Science, 186, 632–634,
https://doi.org/10.1126/science.186.4164.632, 1974. a
Mülmenstädt, J., Sourdeval, O., Delanoë, J., and Quaas, J.:
Frequency of Occurrence of Rain from Liquid-, Mixed-, and Ice-Phase Clouds
Derived from A-Train Satellite Retrievals: RAIN FROM LIQUID-
AND ICE-PHASE CLOUDS, Geophys. Res. Lett., 42, 6502–6509,
https://doi.org/10.1002/2015GL064604, 2015. a
Murray, B. J., Broadley, S. L., Wilson, T. W., Bull, S. J., Wills, R. H.,
Christenson, H. K., and Murray, E. J.: Kinetics of the Homogeneous Freezing
of Water, Phys. Chem. Chem. Phys., 12, 10380–10387,
https://doi.org/10.1039/c003297b, 2010. a
Naud, C. M., Posselt, D. J., and van den Heever, S. C.: A
CloudSat–CALIPSO View of
Cloud and Precipitation Properties across Cold Fronts over the
Global Oceans, J. Climate, 28, 6743–6762,
https://doi.org/10.1175/JCLI-D-15-0052.1, 2015. a
Nelson, J.: Sublimation of Ice Crystals, J. Atmos.
Sci., 55, 910–919, 1998. a
Pasquier, J. T., Pfahl, S., and Grams, C. M.: Modulation of Atmospheric River
Occurrence and Associated Precipitation Extremes in the North
Atlantic Region by European Weather Regimes, Geophys. Res.
Lett., 46, 1014–1023, https://doi.org/10.1029/2018GL081194, 2019. a
Pinto, J. O., Curry, J. A., and Intrieri, J. M.: Cloud-Aerosol Interactions
during Autumn over Beaufort Sea, J. Geophys. Res.-Atmos., 106, 15077–15097, https://doi.org/10.1029/2000JD900267, 2001. a
Proske, U., Bessenbacher, V., Dedekind, Z., Lohmann, U., and Neubauer, D.: Data for the publication “How frequent is natural cloud seeding from ice cloud layers (
Proske, U., Bessenbacher, V., Dedekind, Z., Lohmann, U., and Neubauer, D.: Scripts for the publication “How frequent is natural cloud seeding from ice cloud layers (
Purdy, J. C., Austin, G. L., Seed, A. W., and Cluckie, I. D.: Radar Evidence of
Orographic Enhancement Due to the Seeder Feeder Mechanism, Meteorol.
Appl., 12, 199–206, https://doi.org/10.1017/S1350482705001672, 2005. a
Robichaud, A. J. and Austin, G. L.: On the Modelling of Warm Orographic Rain by
the Seeder-Feeder Mechanism, Q. J. Roy. Meteor.
Soc., 114, 967–988, https://doi.org/10.1002/qj.49711448207, 1988. a
Roe, G. H.: Orographic Precipitation, Annu. Rev. Earth Planet.
Sc., 33, 645–671, https://doi.org/10.1146/annurev.earth.33.092203.122541, 2005. a
Rössler, O., Froidevaux, P., Börst, U., Rickli, R., Martius, O., and Weingartner, R.: Retrospective analysis of a nonforecasted rain-on-snow flood in the Alps – a matter of model limitations or unpredictable nature?, Hydrol. Earth Syst. Sci., 18, 2265–2285, https://doi.org/10.5194/hess-18-2265-2014, 2014. a
Rutledge, S. A. and Hobbs, P.: The Mesoscale and Microscale Structure
and Organization of Clouds and Precipitation in Midlatitude
Cyclones. VIII: A Model for the “Seeder-Feeder”
Process in Warm-Frontal Rainbands, J. Atmos.
Sci., 40, 1185–1206,
https://doi.org/10.1175/1520-0469(1983)040<1185:TMAMSA>2.0.CO;2, 1983. a
Schulzweida, U.: CDO User Guide, MPI for Meteorology, Hamburg, Germany, 2018. a
Seifert, P., Ansmann, A., Mattis, I., Althausen, D., and Tesche, M.:
Lidar-Based Profiling of the Tropospheric Cloud-Ice Distribution to Study the
Seeder-Feeder Mechanism and the Role of Saharan Dust as Ice Nuclei, in:
Proceedings of the 8th International Symposium on Tropospheric
Profiling, edited by: Apituley, A., Russchenberg, H. W. J., and Monna, W.
A. A., p. 5, Delft, the Netherlands, Organizing Committee of the 8th International Symposium on Tropospheric Profiling, 2009. a, b, c, d
Seinfeld, J. H. and Pandis, S. N.: Atmospheric Chemistry and Physics: From Air
Pollution to Climate Change, 2nd edn., J. Wiley, Hoboken, N.J., 2006. a
Soden, B. J. and Held, I. M.: An Assessment of Climate Feedbacks in
Coupled Ocean-Atmosphere Models, J. Climate, 19, 3354–3360,
https://doi.org/10.1175/JCLI3799.1, 2006. a
Stephens, G., Winker, D., Pelon, J., Trepte, C., Vane, D., Yuhas, C., L'Ecuyer,
T., and Lebsock, M.: CloudSat and CALIPSO within
the A-Train: Ten Years of Actively Observing the Earth
System, B. Am. Meteorol. Soc., 99, 569–581,
https://doi.org/10.1175/BAMS-D-16-0324.1, 2018. a
Stephens, G. L., Vane, D. G., Boain, R. J., Mace, G. G., Sassen, K., Wang, Z.,
Illingworth, A. J., O'connor, E. J., Rossow, W. B., Durden, S. L., Miller,
S. D., Austin, R. T., Benedetti, A., Mitrescu, C., and the CloudSat Science
Team: The CloudSat Mission and the A-Train: A New Dimension
of Space-Based Observations of Clouds and Precipitation,
B. Am. Meteorol. Soc., 83, 1771–1790,
https://doi.org/10.1175/BAMS-83-12-1771, 2002. a
Stephens, G. L., Vane, D. G., Tanelli, S., Im, E., Durden, S., Rokey, M.,
Reinke, D., Partain, P., Mace, G. G., Austin, R., L'Ecuyer, T., Haynes, J.,
Lebsock, M., Suzuki, K., Waliser, D., Wu, D., Kay, J., Gettelman, A., Wang,
Z., and Marchand, R.: CloudSat Mission: Performance and Early Science
after the First Year of Operation, J. Geophys. Res., 113,
D00A18, https://doi.org/10.1029/2008JD009982, 2008. a, b
Sullivan, S. C., Barthlott, C., Crosier, J., Zhukov, I., Nenes, A., and Hoose, C.: The effect of secondary ice production parameterization on the simulation of a cold frontal rainband, Atmos. Chem. Phys., 18, 16461–16480, https://doi.org/10.5194/acp-18-16461-2018, 2018. a
Sun, Z. and Shine, K. P.: Parameterization of Ice Cloud Radiative
Properties and Its Application to the Potential Climatic Importance
of Mixed-Phase Clouds, J. Climate, 8, 1874–1888,
https://doi.org/10.1175/1520-0442(1995)008<1874:POICRP>2.0.CO;2, 1995. a
Tan, I., Storelvmo, T., and Zelinka, M. D.: Observational Constraints on
Mixed-Phase Clouds Imply Higher Climate Sensitivity, Science, 352, 224–227,
https://doi.org/10.1126/science.aad5300, 2016. a
Wegener, A.: Thermodynamik Der Atmosphäre, J. A. Barth, Leipzig,
1911. a
Wernli, H., Boettcher, M., Joos, H., Miltenberger, A. K., and Spichtinger, P.:
A Trajectory-Based Classification of ERA-Interim Ice Clouds in the
Region of the North Atlantic Storm Track, Geophys. Res. Lett.,
43, 6657–6664, https://doi.org/10.1002/2016GL068922, 2016. a, b, c, d
Williams, K. D. and Tselioudis, G.: GCM Intercomparison of Global Cloud
Regimes: Present-Day Evaluation and Climate Change Response, Clim.
Dynam., 29, 231–250, https://doi.org/10.1007/s00382-007-0232-2, 2007. a
Winker, D. M., Pelon, J., Coakley Jr., J. A., Ackerman, S. A., Charlson, R. J.,
Colarco, P. R., Flamant, P., Fu, Q., Hoff, R. M., Kittaka, C., Kubar, T. L.,
Treut, H. L., Mccormick, M. P., Mégie, G., Poole, L., Powell, K., Trepte,
C., Vaughan, M. A., and Wielicki, B. A.: The CALIPSO Mission: A Global
3D View of Aerosols and Clouds, B. Am.
Meteorol. Soc., 91, 1211–1230, https://doi.org/10.1175/2010BAMS3009.1, 2010. a, b
Witkowski, M. M., Vane, D., and Livermore, T.: CloudSat – Life in
Daylight Only Operations (DO-Op), in: 15th International
Conference on Space Operations, American Institute of Aeronautics and
Astronautics, Marseille, France, https://doi.org/10.2514/6.2018-2562, 2018.
a, b
Wolf, V., Kuhn, T., Milz, M., Voelger, P., Krämer, M., and Rolf, C.: Arctic ice clouds over northern Sweden: microphysical properties studied with the Balloon-borne Ice Cloud particle Imager B-ICI, Atmos. Chem. Phys., 18, 17371–17386, https://doi.org/10.5194/acp-18-17371-2018, 2018. a, b, c, d
Short summary
Ice crystals falling out of one cloud can initiate freezing in a second cloud below. We estimate the occurrence frequency of this natural cloud seeding over Switzerland from satellite data and sublimation calculations. We find that such situations with an ice cloud above another cloud are frequent and that the falling crystals survive the fall between two clouds in a significant number of cases, suggesting that natural cloud seeding is an important phenomenon over Switzerland.
Ice crystals falling out of one cloud can initiate freezing in a second cloud below. We estimate...
Altmetrics
Final-revised paper
Preprint